139
FXUS65 KRIW 230346
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
946 PM MDT Sun Sep 22 2024

.KEY MESSAGES...

- Dry and seasonal the next few days. A weak cold front Monday brings
  a breezy north wind.

- A warming trend starts the middle of the week, with 80 degree
  temperatures returning for many locations. No precipitation
  expected through the end of next week.

&&

.DISCUSSION...
Issued at 1234 PM MDT Sun Sep 22 2024

An upper low to the south continues to shift eastward today. As a
result, some warmer air is allowed to filter in over Wyoming. Highs
today will therefore be more seasonal, (compared to yesterday`s
cooler temperatures) with highs generally in the 68F to 78F
range. No precipitation expected today, with a mostly to
completely clear sky.

The next weather feature moves in by early Monday morning, as a
trough moves through the area. Model trends have continued to dry
out this system, with recent runs even shifting the trough axis
eastwards. Have removed precipitation chances for Monday as hi-res
models are in agreement on the dry conditions; would just expect
some increased cloud cover. The main impact from this trough will be
the dry cold front that pushes through. The front should begin to
push in from the north by about sunrise Monday morning. As the front
pushes southward, a breezy north wind follows. North wind prone
locations, such as the Bighorn Basin and Johnson County, could see
gusts 20 to 25 mph with this front, with maybe some near 30 mph
gusts with the initial push of the front. As the back of the trough
moves through between late afternoon and the evening, another
surge of winds near 30 mph are possible for these locations.
Models seem to be underplaying the highest wind gusts a little
bit, so have increased the winds in the forecast a bit around
late afternoon to early evening. Elsewhere, gusts up to around
25 mph occur with this frontal passage. Some locations, such as
South Pass, could see some higher gusts as wind flows off the
mountains when winds shift from the west to north. Winds
decrease everywhere into Monday night.

High pressure begins to build in Tuesday, with temperatures coming
up. Long range models keep high pressure over the area through the
rest of next week. This brings warming temperatures and dry
conditions. Many locations could see the return of 80 degree
temperatures, with possible near-record highs.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 945 PM MDT Sun Sep 22 2024

VFR prevails at all terminals through the TAF period. Clouds
will increase from the north for the first few hours of the
period, as a trough and associated cold front approach the
forecast area. SCT-BKN FL150-200 will spread southward across
the forecast area after 06Z and mainly impact areas east of the
Divide. These clouds will scatter out after 00Z Tuesday. A
north wind around 10-15kt follows the front which reaches KCOD
and nears KWRL between 15Z-18Z/Monday. Speeds will be higher at
non- TAF airports KBYG and KGEY. The front pushes into central
Wyoming during the afternoon switching the wind to the north to
northwest. Winds east of the Divide will decrease after 02Z,
with north-northwest winds continuing for KBPI/KPNA and KRKS.

Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for
the latest information on smoke, icing, and turbulence
forecasts.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Wittmann
AVIATION...LaVoie/CNJ